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本文转自:https://baijiahao.baidu.com/s?id=1655231428286780407&wfr=spider&for=pc 上世纪90年代初,交换机市场鸿蒙初开、天地混沌。 不仅厂商们群雄乱战,连交换机的协议和标准都还格局未定。令牌环、FDDI、ATM这些只出现在新生代网工课本里的技术,各领风骚,互有攻伐。 以太网作为诞生最早却“发育”最慢的协议,在夹缝中生存,丝毫看不出后来一统天下的苗头…… 成立于1984年的思科,关注交换机市场已久,而它破局的利器,正是Catalyst交换机。 1993年,思科完成了创立以来的首次并购,目标是一家叫做Crescendo Communications的初创公司。 虽然日后思科创造了多达200+次并购,但这却是其“人生”第一次,也正是这次收购,开启了思科Catalyst交换机的辉煌时代。 这笔交易的金额是9450万美元,对刚上市3年、股价只有“一块两毛七”(USD)的思科来说,并不是一个小数目。但如果我们知道后来Catalyst交换机的年营收高达150亿美金,就会感叹思科天生就是个并购高手。 回想27年前的那个时代,连网络集线器(HUB)都还远远没有普及,造路由器起家的思科却敏锐的觉察到网络交换机市场,选择果断出手,下“血本”买下Crescen......Read More

本文转自: https://blog.csdn.net/chentaocba/article/details/7704918 学防火墙必知的几个概念 一、区域概念(接口区域) 1、 TRUST 信任区域 UNTRUST 非信任区域 DMZ 非军事区 2、 INSIDE 信任区域 OUSIDE 非信任区域 DMZ 非军事区 二、接口模式 transparent模式:(透明模式) 在transparent模式下,设备检查通过防火墙的数据包,但并不改变ip包头中的任何源地址和目的地址信息。因为它不改变地址,所以保护网内的ip必须在untrust连接的网络内是有效且可寻路的,untrust很可能就接互连网了。 在transparent模式下,对于trust区和untrust区的ip地址就设为0.0.0.0,这样可以使防火墙在网络中不可见。但是,防火墙、vpn和流量管理还是要通过配置设备的策略来生效。防火墙相当于一个2层交换机(2层交换机本身是没有ip地址的)。 route模式(路由模式) 当设备处于route模式下,每一个接口都被设立为route模式或nat模式。不像transparent模式,所有的网口都处于不同的子网当中。这个网口处理通过的流量时不nat,即ip包头中的源地址和端口号都保持不变 NAT模式:(地址转换模式) 当一个网口处于nat模式,防火墙会把从trust口往外的ip包中的源......Read More

本文转自: https://blog.csdn.net/chentaocba/article/details/7716109 要想配置思科的防火墙得先了解这些命令:  常用命令有:nameif、interface、ip address、nat、global、route、static等。  global  指定公网地址范围:定义地址池。  Global命令的配置语法:  global (if_name) nat_id ip_address-ip_address [netmark global_mask]  其中:  (if_name):表示外网接口名称,一般为outside。  nat_id:建立的地址池标识(nat要引用)。  ip_address-ip_address:表示一段ip地址范围。  [netmark global_mask]:表示全局ip地址的网络掩码。  nat  地址转换命令,将内网的私有ip转换为外网公网ip。  nat命令配置语法:nat (if_name) nat_id local_ip [netmark]  其中:  (if_name):表示接口名称,一般为inside.  nat_id: 表示地址池,由global命令定义。  local_ip: 表示内网的ip地址。对于0.0.0.0表示内网所有主机。  [netmark]:表示内网ip地址的子网掩码。  route  route命令定义静态路由。  语法:  route (if_name) 0 0 gateway_ip [metric]  其中:  (if_name):表示接口名称。  0 0 :表示所有主机  ......Read More

本文转自: http://blog.emulatedlab.com/archives/1 为何选择 EVE-NG开篇? 笔者选择 EVE-NG 开篇,是因为 EVE-NG 太好用却不被人熟知,有必要在国内宣传一下。当然,今后的内容不会只以它做内容,范围太小。它,只是一个全能工具。 相信大家在平时学习和工作中,总避免不了实验测试,离不开实验环境,这就给大家推荐一款最好用的模拟器,强烈推荐~~~ 在众多模拟器中,唯独 EVE-NG 更适合大众用户使用: EVE-NG:亦是 Unetlab 最新版,功能强大,完全免费 VIRL:cisco 开发的,只有 cisco 授权的用户才可以使用,收费 GNS3:过去最好的模拟器,免费 Packet Tracert:cisco 开发的模拟器软件,功能简单,只适合入门,目前也有 Android 运行的版本。 IOU 与 Dynamips 早已过时,现在模拟器的趋势是融合这两个模拟器。 Other Emulators,就不再一一列举了。 相信看完这篇文章,您一定会觉得 EVE-NG 就是您的选择。 EVE-NG介绍 EVE-NG(全称 Emulated Virtual Environment- Next Generation),继 Unetlab 1.0 后的 Unetlab 的 2.0 新版本,改了名字,原名是 Unified Networking Lab 统一网络实验室。笔者觉得名字改的非常合理,这款......Read More

本文转自:https://www.petenetlive.com/KB/Article/0000039 Problem You want to set up a Cisco ASA to authenticate users (VPN access for example). Solution Kerberos can only be used as an authentication protocol on the ASA, so its fine for allowing VPN connections but not for assigning policies etc. To work both the ASA and the domain need to be showing accurate time. Step 1: Set the ASA to get time from an External NTP Server 1. Log onto the ASA > Go to “Enable Mode” > Issue the following command; User Access Verification Password: Type help or '?' for a list of available commands. Petes-ASA> enable Password: ******** Petes-ASA# configure terminal Petes-ASA(config)# ntp server source outside Note that’s a public time server in the UK (Manchester University) that I use. you may want to use another. 2. To check the ASA has synchronised issue the a ‘show ntp status‘ command, If you s......Read More

本文转自:https://www.petenetlive.com/KB/Article/0001104 Problem I got sent to Holland this week to look at a firewall deployment, and while I was sat in the Airport, I was going over the job I had to do, when I realised the solution I had suggested had a problem see below; My brief was to provide remote AnyConnect VPN into the network so the client could get their network setup, and manage things remotely. However as I drew the network out in my head I realised that the situation above was what was going to happen. How was I going to fix that? Well firstly I thought ‘Just put on the management firewall, and move .2 and .3 to the main firewalls’. Well thats fine, but it does not leave me room for expansion, or if the client needs to add remote access to a production network. (Which will be needed in the future). Then I thought ‘Can I put a static route on the main firewalls to route to the management firewall’. Which is a......Read More

本文转自:https://www.petenetlive.com/KB/Article/0000069 Problem Below is a walk through for setting up a client to gateway VPN Tunnel using a Cisco ASA appliance.This was done via the ASDM console. The video was shot with ASA version 8.4(2) and ASDM 6.4(5) and the setup process is a lot less painful than it used to be. The original article was written with ASA version 8.0(4) and ASDM 6.1(3), which was a little more difficult so I will leave that procedure below just in case 🙂 ASDM cannot be used on the normal port on the outside interface when using SSL VPN SSL VPN AnyConnect from within an RDP session is not supported (and fails – even with a /console switch). SSL (HTTPS ot TCPport 443) needs to be free (i.e. NOT port forwarded to a web server / exchange server etc). Solution For Older Versions of the ASA/ASDM 1. Open up the&nbs......Read More

本文转自:https://www.petenetlive.com/KB/Article/0000628 Problem Note: With Anyconnect 4 Cisco now use Plus and Apex AnyConnect licensing. When Cisco released the 8.2 version of the ASA code, they changed their licensing model for AnyConnect Licenses. There are two licensing models, Premium and Essentials. Solution Cisco ASA AnyConnect Premium Licenses. You get two of these free with your firewall*, with a ‘Premium License’ you can use the AnyConnect client software for remote VPN Access, and you can access Clientless SSL facilities via the web portal. *As pointed out by @nhomsany “The two default premium licenses available are NOT cross-platform, (i.e. only Mac or Windows). Additionally you can use this license’ model with the Advanced Endpoint Assessment License’, this is the license’ you require for Cisco Secure Desktop. You can also use this license’......Read More

本文转自:https://www.petenetlive.com/KB/Article/0001272 Problem I was setting up a Cisco ASA this week and needed to enable the ability for users to reset their domain passwords when they are about to expire. To actually test that, I needed a test user that had their password either about to expire, or actually expired. As I dint want to wait 42 days, or setup a password policy just for one user, I needed to find a ‘quick and dirty’ fix for one user. Solution You need to open Active Directory Users and Computers, and you need to have ‘Advanced options’ enabled. Locate your user and open their properties > Attribute Editor > Attributes > pwdLastSet. If you want to set it to expired, then set its value to Zero. It should change to <never>, which is not strictly true, it actually changes to 12:00AM January 1st 1601. Note: If you set its value to -1 and apply the change it resets the attribute to the current day and time (you ma......Read More

本文转自:https://www.petenetlive.com/KB/Article/0001273 Problem If you have remote users who connect via VPN, and a policy that forces them to change their password periodically, this can result in them getting locked out without the ability to change their password (externally). If your Cisco ASA is using LDAP to authenticate your users, then you can use your remote AnyConnect VPN solution to let them reset their passwords remotely. Solution Standard LDAP runs over TCP port 389, to allow the ASA to reset the password for the users, it needs to be connected via LDAPS ((TCP Port 636). Your AD server needs to be able to authenticate via LDAPS, by default it will not. I’ve already covered how to set that up in another post see the following article. Windows Server 2012 – Enable LDAPS So, assuming your AD server(s) that the Cisco ASA is authenticating against is already setup, you need to ensure that your AAA Settings for LDAP is set to use port 636. Ena......Read More